An allergy is a disorder of the immune system and is characterized by the occurrence of allergic reactions to normally harmless environmental substances. Allergies are caused by antigens. In the case of a food allergy, for example, an individual may experience an adverse immune response to a food allergen. Food allergens are typically naturally-occurring proteins in foods or derivatives that cause the abnormal immune responses. Common food allergens are found in shellfish, peanuts, tree nuts, fish, milk, eggs, soy and fresh fruits.
For example, certain individuals may experience digestive or health problems caused by eating gluten. Gluten is a term commonly used to represent an allergenic class of proteins found in wheat, barley, and rye. Wheat is a grain most commonly found in breads, pastas, and cereal. Wheat often appears in foods like soups and salad dressings as well. Barley is commonly found in beer and in foods containing malt. Rye is most often found in rye bread, rye beer, and some cereals. Individuals that have a wheat allergy or gluten autoimmune disorder caused by Celiac disease need to avoid wheat or gluten in their diet to prevent adverse health effects.
For manufacturers of food products that are labeled as lacking certain common food allergens, regular testing may be performed on product samples to validate the accuracy of the allergen-free claims. One type of test that is typically performed to detect allergens is an enzyme-linked immunosorbent assay, also called ELISA. In an ELISA test, an antigen is immobilized to a solid surface and then complexed with an antibody that is linked to an enzyme. Antigen detection is then accomplished by assessing the conjugated enzyme activity via incubation with a substrate to produce a measureable product. While accurate, ELISA is relatively slow test that typically can only be performed on a limited sample size.